Device for controlling movement of a drop box on a loom



May 30, 1967 TZ 3,322,160

DEVICE FOR CONTROLLING MOVEMENT OF A DROP BOX ON A LOOM FiledJune 17. 1965 2 Sheets-Sheet 1 F. LUTZ May 30, 1967- DEVIGE FOR CONTROLLING NOVEMENT OF A DROP BOX ON A LOOM 2 Sheets-Sheet 2 Filed June 17, 1965 United States Patent 3,322,160 DEVICE FOR CONTROLLING MOVEMENT OF A DROP BOX ON A LOOM Friedrich Lutz, Rothaus, Durnten, Zurich, Switzerland, assiguor to Ruti Machinery Works Ltd., formerly Casper Honegger, Ruti, Zurich, Switzerland, a corporation of Switzerland Filed June 17, 1965, Ser. No. 464,737 Claims priority, application Switzerland, June 18, 1964, 8,015/ 64 14 Claims. (Cl. 139-182) The present invention relates to a device for controlling movement of a drop box on a loom which is adapted to be positioned in various picking positions by a drop box motion, and in particular to a device providing a coupling means having a working position in which said drop box motion is normally coupled to said drop box during operation of the loom.

In looms with which threads or yarns of varying properties, such as for example varying colors, are woven, a special shuttle is provided for each thread or yarn sort. The drop box for carrying the shuttles in the rest positions has a separate compartment for each individual shuttle. The insertion of the various threads as picks is effected in accordance with a pre-determined program which fixes the alternate settings for operation of the various shuttles.

This operation is effected in such manner that the various compartments of the drop box are, according to the program, moved into a working position so that the desired shuttle sequence or the prescribed sequence of threads may be accomplished. The pre-determined program may be determined by punched cards. By means of the latter, that is in accordance with the arrangement of the apertures therein, a drop box motion is controlled so that its movements are determined by the program and are transmitted to the drop box via a transmission coupling means.

It may happen during the operation of the loom that a shuttle does not take up the correct position of rest in the shuttle box. If, for example, the shuttle still projects a short distance out of the drop box, it will block the movement of the drop box; this may result in damage to the weaving loom. Primarily, damage may take place at any machine part as a direct result of the jamming of the mechanism or, secondarily, in consequence of the immediately following picking motion of the pick.

It is the object of the present invention to overcome these disadvantages. The invention is characterized in that the coupling means has, on both sides of its working position, positioning positions corresponding .to the number of maximum possible picking positions of the drop box into which the drop box can be changed; the working position and the positioning positions provide stable coupling states and the locations between these positions form unstable coupling states. The invention is also characterized in that an indicator means is provided which, when the coupling means is moved out of its working position, supplies an indication or signal to actuate a shut-oil device which stops the weaving loom.

If, during a box change, the drop box encounters a resistance which is greater than the force which maintains the coupling means in one of its stable coupling states, the coupling means permits deflection to another stable coupling state. In this manner, the coupling means automatically again positions the drop box in one of the stable positioning positions so that when the picking motion follows, the drop box is in a proper position for picking. Finally, the coupling means is so designed that each time a deflection has taken place, an indication is given which is used for stopping the loom.

3,322,160 Patented May 30, 1967 The invention will now be discussed with reference to embodiments and to the accompanying drawings, wherein:

FIGURE 1 shows a diagrammatic lateral view of a device having coupling means according to the invention;

FIGURE 2 shows a front elevation of the drop box;

FIGURE 3 shows a diagrammatic lateral view of a variant of the coupling means according to the invention; and

FIGURE 4 shows a diagrammatic lateral view of a further embodiment of the invention.

FIGURE 1 shows a drop box motion 11, which has two pivots 12 and 13 that rotate and, depending on the orders of a punch card (not shown), displace cranks 14 and 15 connected therewith into the position shown or into the position rotated through relative thereto. With the cranks 14 and 15, as FIGURE 1 shows, rods 16 and 17 are coupled in such manner as to be pivotal about the pivots 18 and 19, respectively. Pivots 18 and 19 are connected to the two-armed lever 22 in such manner as to be pivotal about the pivots 20 or 21, respectively. Lever 23 carries the two-armed lever 22 through the agency of a pivot 24 and is pivotal about a pivot 30 (which is secured on a fixed portion 25 of the machine frame).

Pivotal about the pivot 24 is a connecting rod 26 that connects the drop box motion 11 with the transmission coupling means 27. Said coupling means comprises a rotary body 29 which is rotatable about a pivot 28 and which on the one hand comprises a circular-sector body with grooves 60 and 61 and on the other hand comprises an arm 29. The connecting rod 26 is secured by means of a pivot 32 to the outer end of arm 29'. Pivot 28 is secured to the machine frame by means of a carrier 31. A twoarmed lever 34 is mounted in such manner as to be pivotal about a pivot 33 on a carrier 32 which is also secured to the machine frame. Lever 34 is subjected to an anticlockwise rotational force by'means of tension spring 35. This force produces, via lever 34 and a roller 36 secured thereto, an upwardly directed pressure on the horizontal arm 37a of a cranked lever, the other arm of which is designated by reference numeral 37b. Since the angle-lever having arms 37a and 37b is pivotal about a pivot 38, it is subjected to a clockwise rotational force. Consequently, a roller or biased member 39 is pressed into groove 60, as shown in FIGURE 1.

The pivot 38 holds a lever 40, which is also pivotal about pivot 28 and to which a carrier rod 41 is secured. Secured to :the upper endof the carrier rod is a drop box 42. The drop box has compartments 43 to 46, inclusive, with shuttles 43' to 46, inclusive, being disposed in each of said compartments. In order that the drop box may be guided exactly in its longitudinal direction, guides 79, which are secured to the loading frame, are provided. Carrier rod 41 has jointed connections 91 and 92, respectively, at its ends.

Secured on the two-armed lever 34 is a control rod 48 which is so mounted as to be pivotal about pivot 47. The control rod actuates a rod 55 rotatably mounted on connecting member 54. Rod 55 has a projection 51 engaged on a holding member 56. The holding member is secured to an actuating lever 52 which is retained in its position by means of a retaining lever 57. The retaining lever is tensioned by tension spring 68, with the projection 65 holding the projecting arm 67 secured to actuating lever 52.

Via the connecting member 54 and double lever 58, spring 53 endeavors to release drive coupling 59, which couples the driving motor :to the main shaft of the loom and thereby acts to separate the drive from the weaving loom. As long, however, as rod 55 is retained on holding member 56 by projection 51, the driving motor is coupled to the loomn.

FIGURE 2 shows a front elevation of drop box 42 with the shuttles 43' to 46 contained therein. Furthermore, this figure shows a sley 62 and a run-in member 63 for guiding of the shuttles.

I In the operation of the device described hereinabove, the control of the punched card causes pivots 12 and 13 of thedrop box motion 11 to position cranks 14 and 15 in the position illustrated or in the position rotated through 180 relative thereto. If, for example, crank 14 is in the illustrated position and crank 15 is in the position rotated by '180 about the pivot 13 relative thereto, then this brings about a displacement of the pivot 21 toward the right.

:T his also produces a displacement of the pivot 24 toward the right, although the magnitude of this displacement is smaller than the displacement of the pivot 21, since of course pivot has retained its position. If pivot 24is 'to be moved toward the right for a relatively larger distance, the control action of the punched card must produce a 180 rotation of crank 14 and must keep crank 15 in the position illustrated. The relatively larger movement toward the. right 'is accomplished because pivot 24 is closer to pivot 20 than to pivot 21. It will be obvious that rotation of both cranks 14 -and.15 through 180 relative to the position shown in FIGURE 1 will produce the maximum displacement toward the right of the pivot24.

The movement of pivot 24 is transferred to rotary body 29 via connecting rod 26. In this manner, the four different positions (mentioned hereinabove) of the pivot 24 correspond to'difierent angular positions of the rotary body. Since roller 39- is pressed into groove 60 by means of spring 35, it will be appreciated that, when the rotary body rotates, roller 39, the angle lever with arms 37a and 37b, the pivot 38and the lever 40 together with carrier rod and the drop box are constrained. In this way, an adjustment'of the drop box in accordance with the control provided by the punched card is achieved. The shape of the arcuate travel curve 50 at the end portio-n of arm 37a is so selected that in each of the dilferent angular positions of the rotary body and of lever 40, lever 34 does I not 'vary its angular position as in groove 60.

If, for any reason whatsoever, movement of the drop box' is hindered, for example, due to the fact that a long as roller 39 remains shuttle, as shown'in FIGURE 2, does not come to a standstill in its prescribed'rest position, then, if the drop a predetermined value, which is determined by spring 35. According to the invention, there are on both sides of the'working groove 60, grooves 61 which form positioning positions, the working groove 60 being advantageously deeper than the positioning grooves 6-1.

Assuming, for example, that the drop box 42 is compelled, in accordance with an order from a punched card, to move downwardly .by the amount of two positions but; is (as shown in FIGURE 2) jammed by the shuttle 43.: The drop .box motion brings about the rotation of rotary. body' 29 but roller 39 takes up its position in that groove 61 which, inthe position shown in FIGURE 1, is

under lever The roller 39.endeavors constantly to take up its position inthe deepest portion of a groove. This. is caused by the pressure on the roller 39'produced by the pull of the spring 35 via lever '34 and the cranked lever having arms 37a and 37b. In this way, the advantage is'obtained that, in the event of jamming which holds the drop box in a position between two of its regular positions, as prescribed for the shuttle pick, the drop box cannot remain in this position but always passes into a position which is prescribed for the picking (that is, the

drop box is properly positioned in relation to the sley). Only those positions of the coupling means 27 are stable in which the roller 39 has dipped into the grooves 60 or 61 to the maximum depth. These positions are, on the other hand, so selected that they correspond to the four picking positions of the drop box 42 prescribed for the picking motion and determined by the four difierent positions of the rod 26 moved by the drop box motion 11. Thus, during a following picking motion, there is no danger that the picking stick might damage or destroy the drop box, the shuttle or any other part of the weaving loom; The only consequence of jamming of the drop box 42 is in that, during the next picking motion, the wrong shuttle is struck, that is, an incorrect thread is picked, unless the loom can beforehand be brought to a standstill.

In the event of incorrect operation of the drop box 42 and consequently of displacement of the roller 39 out of its working position 60 into one of the positioning positions 61, the roller 39 is, as it is transferred fromone groove to the other, pressed somewhat outwardly. In consequence of this, the angle lever having arms 37a and 37b rot-ates anti-clockwise. During'this movement, roller-36 is pressed downwardly and again produces a rotation in the clockwise direction of the two-armed lever 34. The lifting resulting therefrom of pivot .47 and of control rod 48 produces an indication which indicates or signals the incorrect mode of operation and serves to shut down the loom.

According to the present embodiment, the indication is used for lifting of rod 55, that is, for rotating the connecting member 54, so that projection 51 is released from engagement withrthe holding member 56 and, consequently, the tension spring 53 is released. The spring is thus able to rotate the two-armed lever 58 clockwise so that the drive coupling 59 between the loom-driving motor and the loom is interrupted. At the same time, by braking means which are not shown,.immediate braking of the machine is initiated. After the defect has been eliminated, the drive coupling is again switched on by actuating lever 52. Actuation of lever 52 is possible inasmuch as its fixe position has been released by retaining lever 57.

In order that under all circumstances, that is with every positional change which may take place of the drop box 42, the drop box may always pass into a rest position which has been prescribed for a picking motion, thereare, as the above example shows, on both sides of the working position as many positioning positions available as there sitioning positions must be provided upwardly from the working position on the rotary body 29. If the drop box were tobe in its lowermost position, there would be three box or picking positions located above intowhich the drop box could be ordered to travel by instructions on thepunched card. Thus, for this case, it is also necessary to provide three positioning grooves 61 on the lower half of the rotary body 29.

Advantageously, the positioning grooves 61 are made shallower than the working groove 60. By means ofthis measure, the result is achieved that starting-up of the loom is not possible so long as the roller 39 is not in the working position corresponding to groove 60; that is, for example, if it has been overlooked'that the machine has been shut down due to the fact that the roller 39 has moved out of its working position. This is due "to the fact, that, in consequence of the shallower depth of the positioning positions as'compared with the working position, under such circumstances rod 48 is not moved sufficiently downward to cause projection 51 to engage; thus, as long as the roller 39 is in a positioning position, rod 55 is not influenced byactuation of lever 52.

t It is a further advantage of the device described that it permits easy changing of the shuttles disposed in the drop box. For example, if the second shuttle from the top is to be removed for any reason and if the drop box is (as shown in FIGURE 2) in its uppermost position, then the drop box is released from the rotary body 29 by pressure on the pedal 64 at the end of lever 34. Simultaneously, by a guiding action with the aid of handle 65 secured to the carrier rod, the drop box is lowered to such an extent that the shuttle (shuttle 45') adopts a position between the sley 62 and the run-in member 63. When the pedal is released, the drop box is then adjusted precisely in its picking position prescribed for the actuation of the shuttle by the restored pressure on roller 39 produced by the spring 35. In this manner, easy takeout and introduction of the shuttles is made possible. A stop 66 is provided in order that lever 34 may not be rotated farther than is necessary.

FIGURE 3 shows a further embodiment of a transmission coupling means. For like parts, the same reference numerals employed in FIGURE 1 have been used. Connecting rod 26 secured to the drop box motion is again pivotal about pivot 32 and is connected with rotary body 29, whereby a reciprocating movement of rod 26 produces a rotary movement of body 29 about pivot 28. By means of this rotary movement, roller 39, which is pressed by a compression spring 71 into working groove 60, and lever arm 40 connected with the roller via a connecting member 72 are also moved about the pivot 28. The connecting member is secured on the lever arm in such manner as to be pivotal about pivot 69.

It will be apparent that the mode of operation of the coupling means shown in FIGURE 3 is similar to that of the coupling means shown in FIGURE 1. A dilference, however, resides in the arrangement for the pressingon of the roller against the rotary body. This difference is due to the fact that, instead of a mechanical indicator device for indicating when the roller 39 is no longer in working groove 60, according to FIGURE 3 an electrical indicating device is provided. This indicating device comprises a pin 73 which is movable in its longitudinal direction and which is secured to a contact member 74. A spring 75 endeavors to press the contact member toward the right, that is in the direction of the roller. A long as the roller is in the working groove, however, the pressure thereof (which is produced by spring 71) holds the contact member in contact with two contacts 76. Two electrical conductors 78 formed by movable cables are connected with the contacts 76. As long as the two cables are electrically connected by contact member 74 via contacts 76, a current flowing through them holds a relay (not shown). In the holding state, the relay causes a drive coupling to be engaged between the loom-driving motor and the loom. Since this is a conventional arrangement, it is not shown in the drawings.

During a drop box change, if movement is hindered and a predetermined force is exceeded (as in the example according to FIGURES l and 2), roller 39 is moved out of working groove 60. The roller will, due to the force exerted by spring 71, descend to the lowest portion of a position groove 61 in consequence of which, not the desired shuttle but one of the shuttles or one compartment of the shuttle box is put in a correct posiiton for the picking motion. By this means, damage to the loom or parts is prevented.

FIGURE 4 shows a further embodiment of the present invention. Those parts which are identical with parts of FIGURE 1 have again been given the same reference numerals. A horizontal movement of connecting rod 26 produces, via the connection through the agency of pivot 32, a pivoting movement of lever 80 about the pivot 28 secured on stationary carrier 31. Secured on lever 80 is a movable body 81 formed with a groove 60 defining the working position and with grooves 61 defining positioning positions, said movable body being secured by a sliding and retaining arrangement having a slot 82 and pins 83 sliding therein. For rectilinear guiding, the movable body is provided with a slot 84 which together with a guide plate 85 secured to the sley frame provides for the rectilinear guiding. Both ends of the movable body 81 have sliding and retaining means 86 in which a carrier rod 41 is able to slide. Furthermore, there is a wedge or biased member 87 which ispressed outwardly in a guide 89 by means of a compression spring 88. The carrier rod is secured to the guide 89. A pin is secured to the Wedge. The pin transmits its movement to a Bowden cable 95 via an angle lever 94 that is pivotal about pivot 93.

The spring 88 is so pre-tensioned that, under normal operational conditions, an upward and downward movement of the movable body contains the wedge 87 and also the carrier rod 4-1 with drop box 42. If for any reason whatsoever the resistance to the upward or downward movement of the drop box becomes excessive, the wedge is pressed toward the right and, as the carrier rod slides in means 86, only body 81 is moved. Under these circumstances, wedge 87 is moved out of the working groove 60 and takes up its position in one of the positioning grooves 61. Consequently, at the instant of the following picking motion, one of the compartments 43 to 46 is in one of the positions prescribed for the picking. It will be appreciated that, due to the pressure of the spring 88, the wedge is forced into the lowest position in one of the grooves 60 or 61 since only these lowest positions are stable.

If the wedge moves out of the working groove, pin moves toward the right as the wedge passes from the groove 60 into the adjacent groove 61. As a result, the inner wire 96 of the Bowden cable 95 is actuated via the angle lever 94 so that an indication of the incorrect operation is given. The actuation of the Bowden cable is utilized, in combination with known means, for uncoupling the driving motor from the loom and braking the latter.

It will be seen from FIGURE 4 that in this embodiment the working groove 66 is also deeper than the positioning groove 61. In this Way, it becomes possible to utilize the indication provided by the Bowden cable in such manner that each position of the wire 96 which does not correspond to the maximum insertion of wedge 87 in groove 60 is utilized as a signal for stopping the loom. Re-starting the loom with the drop box wrongly positioned is thereby avoided.

A further variant for producing an indicating signal is obtained with a coupling means wherein, in contradistinction to the example of FIGURE 3, groove 60 is not provided with a contact. Instead, there are contacts that can be actuated by roller 39, at least in the positioning grooves 61 adjacent the groove 60 and preferably in all the positioning grooves 61. The evaluation of the indication obtained from these contacts is such that the actuation of one of these contacts produces a signal or a signal change by means of which another device is actuated for uncoupling the loom from the drive and exerting a braking action thereon.

While the novel features of the invention have been shown and described and are pointed out in the appended claims, it is to be understood that various omissions, substitutions and changes in construction and arrangement of the features shoWn and described may be made by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. In a loom, a device for controlling movement of a drop box adapted to be positioned in various picking positions by movement of a drop box motion, which comprises coupling means operably associated with said drop box motion for positioning said drop box, said coupling means having a working position in which it is normally coupled to said drop box operation of said loom and also having positioning positions on both sides of said working position, the number of positioning positions corresponding to the maximum number of possible picking positions into which the drop box can be changed, the working position and the positioning positions forming stable coupling states and the locations between these positions forming unstable coupling states, means for allowing said coupling means to shift to one of said positioning positions when movement of said drop box is hindered, and an indicator means which supplies an indication for actuating a shutofi mechanism for stopping the loom when the coupling means is coupled to said drop box in one of said positioning positions.

2. A device according to claim 1 in which the Working position has a design that differs from that of the positioning positions, the difference in the design being utilized for producing said indication.

3. In a loom, a device for controlling movement of a drop box adapted to be positioned in various picking positions by movement of a drop box motion, which comprises coupling means operably associated with said drop box motion for positioning said drop box, said coupling means having a working position in which it is normally coupled to said drop box during operation of said loom and also having positioning positions on both sides of said working position, the number of positioning positions corresponding to the maximum number of possible picking positions into which the drop box can be changed, the working position and the positioning positions forming stable coupling states and the locations between these positions forming unstable states; said coupling means comprising at least two movable parts, a first part being adapted to be actuated by the drop box motion and a second part being coupled with the drop box, one of said parts providing the working position and the positioning positions and the other part having means for biasing it towards said one part whereby retaining arrangements are provided between said parts for allowing said coupling means to shift to one of said positioning positions when movement of said drop box is hindered and an indicator means'which supplies an indication for actuating a shutoff mechanism for stopping the loom when the coupling means is coupled to said drop box in one of said positioning positions.

4. A device according to claim 3 in which a foot pedal, when actuated, releases the biased retaining arrangements between the parts of said coupling means for allowing manual adjustment of the drop box between the stable positions of said coupling means.

5. A device according to claim 3 in which one of said parts has a first groove forming the working position and additional grooves forming the positioning positions on either side of said first groove and said other part includes a biased member adapted to be pressed into each of said corresponding to the working position is deeper than the grooves corresponding to the positioning positions, and the indicator means supplying the indication comprises a linkage means which is coupled with the member which is adapted to be inserted, whereby said linkage means controls an indicating mechanism in dependence on the insertion depth of the member.

7. A device according to claim 5 in which said member is a roller pressed against the grooves by a resilient means.

8. A device according to claim 5 in which the grooves are V-shaped and said member is a wedge which is pressed against the grooves by resilient means.

9. A device according to claim 5 in which one of said parts has said grooves on its periphery and is pivotable about a pivot and the other part includes an arm jointedly secured to said member and pivotable about said pivot, said member being pressed by a resilient means against said grooves so as to provide a reciprocal coupling of the parts.

10. In a loom, a device for controlling movement of a drop box adapted to be positioned in various picking positions by movement of a drop box motion, which comprises coupling means operably associated with said drop box motion for positioning said drop box, said coupling means having a working position in which it is normally coupled to said drop box during operation of said loom and also having positioning positions on both sides of said working position, the number of positioning positions corresponding to the maximum number of possible picking positions .into which the drop box can be changed, the working position and the positioning positions forming stable coupling states and the locations between these positions forming unstable coupling states, said coupling means having at least two movable parts, a first part being adapted to be actuated by the drop box motion and a second part being coupled with a drop box, one of said parts having a first groove forming the working position and additional grooves forming the positioning positions on either side of said first groove; and the other of said parts comprising a member biased by resilient means and adapted to be inserted in each of said grooves, whereby one of said parts and the member are pressed against each other, said member being operably associated with linkage means whereby said linkage means is moved out of its normal position when said member is moved out of the working position formed by the first groove, movement of said linkage means supplying an indication for actuating a shut-off mechanism for stopping said loom.

11. A device according the claim 10 in which said linkage means comprises a movable lever by which said member is pressed-on by said resilient means; movement of said lever serving as the indication for actuating saidshut-oif mechanism.

12. A device according to claim 10 in which said linkage means comprises a pressure member which, when it is moved out of its normal position, actuates an electrical contact for producing indication that actuates said shutoff mechanism.

13. A device according to claim 12 in which the member in the working position holds an electrical contact closed by pressure on the pressure member.

14. A device according to claim 10 in which a pressure member is located in at least each of the positioning positions adjacent the working position, whereby, in the event of the movement out of its normal position, said pressure member actuates an electrical contact for producing the indication that actuates said shut-off mechanism.

' References Cited UNITED STATES PATENTS 554,258 2/1896 Gartner 139182 2,523,648 9/1950 Darwin 139336 r 2,717,008 9/1955 Moss 139-336 FOREIGN PAT ENTS 54,178 12/ 1911 Germany. 655,321 1/1938 Germany. 859,579 12/ 1952 Germany.

MERVIN STEIN, Primary Examiner.

H. S. JAUDON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,322,160 May 30, 1967- Friedrich Lutz It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 72, after "box" insert during Signed and sealed this 5th day of November 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, 11'.

Commissioner of Patents Attesting Officer 

1. IN A LOOM, A DEVICE FOR CONTROLLING MOVEMENT OF A DROP BOX ADAPTED TO BE POSITIONED IN VARIOUS PICKING POSITIONS BY MOVEMENT OF A DROP BOX MOTION, WHICH COMPRISES COUPLING MEANS OPERABLY ASSOCIATED WITH SAID DROP BOX PORTION FOR POSITIONING SAID DROP BOX, SAID COUPLING MEANS HAVING A WORKING POSITION IN WHICH IT IS NORMALLY COUPLED TO SAID DROP BOX OPERATION OF SAID LOOM AND ALSO HAVING POSITIONING POSITIONS ON BOTH SIDES OF SAID WORKING POSITION, THE NUMBER OF POSITIONING POSITIONS CORRESPONDING TO THE MAXIMUM NUMBER OF POSSIBLE PICKING POSITIONS INTO WHICH THE DROP BOX CAN BE CHANGED, THE WORKING POSITION AND THE POSITIONING POSITIONS FORMING STABLE COUPLING STATES AND THE LOCATIONS BETWEEN THESE POSITIONS FORMING UNSTABLE COUPLING STATES, MEANS FOR ALLOWING SAID COUPLING MEANS TO SHIFT TO ONE OF SAID POSITIONING POSITIONS WHEN MOVEMENT OF SAID DROP BOX IS HINDERED, AND AN INDICATOR MEANS WHICH SUPPLIES AN INDICATION FOR ACTUATING A SHUTOFF MECAHANISM FOR STOPPING THE LOOM WHEN THE COUPLING MEANS IS COUPLED TO SAID DROP BOX IN ONE OF SAID POSITIONING POSITIONS. 